Engine, and particularly internal-combustion engine



Jan. 5 1926.

H. MICHEL ENGINE, AND PARTICULARLY INTERNAL COMBUSTION ENGINE Filed Oct.27, 1925 /////////AV///// W// Ii 5 &

' Pa'tenteddan- 5,1926.

nsammu mount; or vooamt, GERMANY."

nnenm, AND PARTICULARLY rn'rmman-oomausrron Enema.

Application filed October 27, 1923. Serial No. 671,193.

To all whom it mag concern:

Be it known that'I, HERMANN MICHEL, a

citizen of Germany, and resident of Voorde,

in Holstein, Germany, have invented certain new and useful Improvementsin Engines, and Particularly Internal-Combustion Engines, of which thefollowing is a specifica- 1tion.

- I My invention relates to engines, and parthe two-cycle type in whichthe pistons coticularly to internal combustion enginesof operate with acam track. When the cam track is stationary and the cylinders rotate,

the arising centrifugal forces enable the engine, during its normalrunning, to operate satisfactorily even if a sin le external cam trackis used, against wh1chbear rollers presslon o I ary internal. cam trackfor positively glVlIlg mounted-directl or indirectly on the pistons.During t e starting operation, however, and also while the engine iscoming to a stop, the centrifugal forces and the comdo not-reach theirnormal values,

in view of this there is added an auxilithe necessa motions to thepistons.

'Since un er the operating conditions explained above the rollers exertpressure on the main cam track and on theauxillary track alternately,there is danger of shocks occurring whenever the direction of suchpressure cha es, and in order to avoid this the distance etween the twotracks has hitherto been made either exactly equal to i the diameter ofsuch rollers, or (when using one roller.to engage the main, track and adifferent rollerto engage the auxiliary track) the diameters of therollers were of such a size that'the rollers would be permanently insimultaneous light contact with the r ective tracks. With suchconstructions, 't e engine will not knock or rattle when the directionof the pressure exerted .on the cams is reversed, just as in engineswith a crank shaft drive all play is avoided order to at the shaftbearings and crank hearings, in d prevent knocking or rattling of therive.

The present invention relates more specially to that typeof an enginehaving a controlling cam, 1n which the cylinders are stationary whereasa fly-wheel or the like carriesthe rotary cam, the main track beingconstructed in such a manner that a single cIa m- .track willsuffice for'a machine of this f'type, during itsjnormal operation. This ret isobtained by designing and constructbon de osits) each' point be smallerthan the checking or retardatlon due to compression. Thus, taking intoconsideration the forces tending to accelerate the mass of the parts ofthe drive, the forces required to retard said parts in accordance w1ththe sha sion stroke, be smaller than the forces which the compressionexerts on the piston. The rollers will therefore always remain incontact with the cam track, assuming, of course, that both compressionand the mass forces of the drive parts have their'normal value and thatin other respects the engine is operating properly. It will beunderstood that in this case also an auxiliary cam track is required toact during the starting of the engine and while it is coming to. a stop.

The present invention contemplates using, in a structure of thecharacter indicated above, a main cam track of the kind mentioned butlocated at a relatively greater distance from the auxiliary cam track,so that the rollers connected with the pistons will not touch theauxiliary track at the of the track will, v

even during the second alf of the compres- I! there will indeed be acertain knock or rat tle during the starting of the engine and while itis coming to a stop, but this is not a serious objection in ractice,and, in fact, it offers a definite a vantage in that this knock producesa distinct readily recognizable sound when there'is any defect, so that'trouble that may endanger the engine if allowed to remain unremedied,will be discovered during starting so that proper repairs or adjustmentsmay be made before any serious harm results.

For instance, friction between a piston and its cylinder may beincreased .undulyby expansion of the iston due to excessive heating, orby the plston rings stickin or seizing owing to combustion residues car-With an engine having a crank rive, or a cam mechanism with rollers inpermanent contact with the respective tracks, the increase in frictionresulting under the circumstances just mentioned will not be perceiveduntil the particular piston becomes tightly jammed and interferes withthe running of the engine, or even causes some part of the. drive tobreak. The damage thus entailed is'very serious. Tit, however, as in mypresent invention, the distance between the two cam tracks is purposelymade greater than absolutely necessary to accommodate the roller, sothat, owing to the increased looseness or play thus provided,; theroller will touch only the main track during the normal running of theengine, the existence of abnormal friction or resistence will berevealed as soon as such disturbance arises, because in that event thegas pressure within the cylinder will be used up in overcoming thefrictional resistance and will therefore be insufl'icient to ive thepiston such an acceleration as to eep its roller continuously againstthe main track. Tn the case of such a disturbance, therefore, therollers will be knocked to and fro between the main track and theauxiliary track, and will thereby, at the very beginning of thedisturbance, produce a pecul ar, readily noticeable hum orrattle.Attention is thus called at once to the existence of trouble, and theroper remedy can be applied before any amage results.

Thus, with constructions as generally emloyed hitherto, particularlywith engmes having a plurality of cylinders, any excessive friction atone of the pistons would be discovered onl after jamming of the pistonhad injure or even broken therespective cylinder. The present invention,however, insures a s ecial cooperation between'the mass acce orationforces oi: the parts of the drive, the gas ressure within the cylinder,and the articu ar shape of the main cam track, enab ing the auxiliarycam track to be utilized for giving an audible indication of any troubleor disturbance, at

the very beginnin thereofiso as to rovide unfailing means or avoiding acy 1 nders being injured by a detective operation of the correspondingpiston.

When ado ting the expedient of causing separate roli ers to engage themain track and the auxiliary track respectively, and if in this case themain roller and the companion auxiliary roller are mounted coaxially onthe same crosshead, the amountof play required for the purposes of mypresent invention can be secured by making the distance between the maincam track and the auxiliary cam track but slightly greater than the sumof the radii of said two rollers.

A satisfactory and preferred embodiment of the present invention isillustrated by the accompanying a section, 'aken lengthwise of the axisof rotation,,, bowing an engine constructed according "to myimprovement; Fig. 2 is a drawings, in which Fig. 1 isitseaeee partialcross section, taken on line 2-2 of Fig. l; and Fig. 3 shows the upperportion of Fig. 1, upon an enlarged scale.

The particular two-cycle internal combustion engine represented in thedrawings has two stationary cylinders, forming a unit 1, supported onone side by a bracket or carrier 14, and containing the opposedreciproeating pistons 2 and 3, connected by rods 4 to the crossheads 5.The latter are movable radially along' stationary guides 6, and carryrollers 7 cooperating with rotary cam tracks. These tracks are formedon, or secured to, rings 15 fastened to fly-disks or fly-wheels 8rigidly connected so'as to move in unison. One of the fly-wheels isjournaled on the carrier 14, the other is connected d rectly to a drivenshaft 17 journaled in a bearing 16. i

Liquid fuel is introduced through an opening 11 into the combustion orworking chamber 18 of the cylinder unit 1, which chamber is common toboth pistons 2 and 3. The scavenging air enters through the scavengingslits l0 controlled by the piston 3, while the exhaust gases escapethrough the slits 9 controlled by the piston 2.

The main or outer tracks cooperating with the rollers 7 are composed oftrack portions or elements each extending from an outer point I; to aninner point a and again to the next outer point 6, each of theseelements controlling a com lete two-cycle operation. The section of eachelement extendmg from the point 0 to the point a, which section controlsthe second half of the compression stroke, 1s given such a configurationthat, during normal running of the engine the forcesrequired to retardthe arts oi the drive in accordance with the s ape of the track will besmaller than the forces which the compression within the chamber 18exerts on the piston. Owing to this arrangement, the rollers 7 will bepressed forcibly and continuously against said main cam tracks as soonas the compression and the mass forces (momentum) of the parts of thedrive have attained their normal values. Therefore, if the normalrunning of the engine were the only operative condition to beconsidered, the main cam tracks Z -a-b would be suflicient.

@n the axles 19 of the rollers 7 are further mounted additional rollers20, which cooperate with the auxiliary (inner) cam tracks b'a-b',arranged in such a relation' to main cam tracks b-ab that the rollers 7and the companion rollers 20 may engage the respective tracks atdiametrically opposite points (with reference to the axis of suchcompanion rollers). The auxiliary cam tracks are providedon annularledges 21 forming part of the fly-wheels 8, and are parallel to saidmain cam tracks. in the particular construction illustrated, in

its

point of the auxiliary cam track ba'-b' and the adjoining main cam trackb-a .-b

is slightly larger than the sum of the radii of said rollers, butsufliciently so to insure the rollers 20 being out of contact with theauxiliary cam track when the companion roller .7 engages the mainviceversa.

During the starting (cranking), of -the engine the piston 2, through itsauxihary rollers 20, bears on the annular ledges 21, that is to say, onthe auxiliary cam tracks, while the piston 3 with its main rollers 7bears on the rings 15, that is to say, on the main cam tracks. Thereforeboth pistons will be given the proper motions for starting, if the shaft17 and'the fly-wheels 8 and the cam tracks connected therewith, arerotated by a starting crank, a so-called selfstarter, or any approvedmechanism'. (not shown). As soon as the engine attains its normalrunning condition, the pressure within'the chamber 18'will cause theauX- iliary rollers 20 of piston 2 to move out of and rotary fiy-wheelsoperated by means of contact with the ledges 21, andthe companionrollers 7 are brought into contamfith the main cam tracks. Thus duringthe normal running of the engine all the rollers 7 carried by the crossheads 5 will be maintained in permanent contact with the main (outer)cam tracks. 7

Should the friction between any piston and its cylinder become excessivefor any reason such as lack of proper lubrication, the continuouscontact between the rollers 7 of that piston and the main track, and theresulting (positive operation, are no longer maintaine the pistonlagging behind, during" the outward stroke since the pressure forcing itoutward is no, longer sufiicient, after overcoming the piston friction,to give the moving parts an acceleration corresponding to the shape ofthe tracks. Owing to such lagging or retardation, .the auxiliary rollers20 will come in contact with the annular ledges 21, but will be pushed aain toward the main tracks, by the action 0 the auxiliary tracks. Thisoperation will be repeated asthe cam tracks rotate, and a characteristic rattling noise will be produced. The engineer, having hisattention attracted by this unusual noise, will thus notice thedefective operation of the piston at the very start of the trouble, andwill therefore be able to apply the proper remedy before material injuryresults. I

The construction set forth herein is applicable not only to internalcombustion engines of the type described, but to any other engine havingstationary cylinders a cam track.

Various modifications may be made withcam track, and

out departing fromv the nature of my invention as defined in theappended claims.

I claim: 1. An engine comprising stationary cylinders, pistonsreciprocating therein, a rotary fly-wheel provided witha main cam track,

operating members connected with the pis-' tons and engaging said camtrack to rotatethe fly-wheel, the latter also having-an auxiliary camtrack for active cooperation with said members during the startingoperation and while the engineis coming to a stop, those portions of themain cam track which are operative during the second half of the inwardpiston stroke being so constructed that the distance between the two'cam tracks is sufficient to keep the said operating members out ofcontact with the auxiliary track when they are in engagement with themain track.

2. An engine comprising stationary cylinders, pistons reciprocatingtherein, a rotary fly-wheel provided with a main cam track, mainoperating rollers connected with the pistons and engaging said cam track-to rotate the fly-wheel, auxiliary rollers likewise connected withsaid'pistons, said fly-wheel.

also havingfan auxiliar cam'track for cooperation with said auxiliaryrollers during the starting operation and while the engine is coming toa stop, those portions of the main cam track which are operative duringthe second half of the inward piston stroke being so constructed thatthe distance between the two camtracks is sufiicient to kee theauxiliary rollers out of contact wit the auxiliary track when the mainoperating rollers. are in engagement with the main track.

3. 'An engine comprising stationary cylinders, pistons reci rocatingtherein, a rotary fly-wheel provid garallel main and auxiliary camtracks of ifierent-diameters, main operating rollers connected with thepistons and engaging said main cam track to rotate the fiy-wheel,auxiliary rollers each coaxial with one of the first-named rollers andadapted for cooperation with said auxiliary track during the startingoperation and while the engine is coming to a stop, those portions ofthe main cam track which are operative during the second half of theinward piston stroke being so constructed that the distance between thetwo cam tracks is sufficiently greater than the sum of theradii of amain roller and the companion auxiliary roller. whereby to keep theauxiliary rollers out of contact with the auxiliary track when the mainoperating rollers are in engagement with the main track.

In testimony whereof I have signed this specification.

HERMANN MICHEL.

ed with concentric and

